Key Takeaways
- Most multi-res roof calls come down to drains, scuppers, parapets, plumbing vent penetrations, HVAC curbs, and aging membrane.
- A proper maintenance plan can push a flat roof 10+ years past its expected service life.
- Roof strategy should match the owner’s goal: long-term hold, pre-sale prep, or stabilizing before a replacement or redevelopment.
In a multi-residential building, the roof is the only thing standing between a satisfied tenant and a disaster. When a flat roof fails, the water doesn’t just sit there—it ends up in someone’s bedroom or kitchen. That changes the stakes. You don’t have weeks to wait for a callback; you need a contractor who understands that an active leak is a ticking clock on your reputation and your bottom line.
Since 1998, we’ve been the “boots on the roof” for apartment buildings, condos, and low-rise multi-res complexes across Southern Ontario. From the Niagara Region to the GTA, we don’t just patch holes, we help owners push their roof’s lifespan well beyond the original spec sheet.
What Goes Wrong on Multi-Res and Condo Roofs
Most repair calls from condo boards and property managers in Toronto, Mississauga, and St. Catharines aren’t for “exotic” problems. They are predictable failures that, if caught early, can be fixed before the interior drywall is ruined.
- Drain & Scupper Failures: Old drains that weren’t properly integrated into the membrane or scuppers that have rusted through. When water backs up, it will find an entry point.
- The Parapet Gap: The joint where the membrane meets the parapet wall is a notorious weak spot. If counterflashing pulls away or parging cracks, water runs down the inside of the wall straight into top-floor units.
- Plumbing Vent Leaks: Every apartment stack breathes through the roof. When a boot or flashing fails, the leak goes directly into a tenant’s bathroom ceiling.
- HVAC Curb Issues: Rooftop units for corridor ventilation and makeup air sit on curbs that require precision flashing. These are often overlooked during general maintenance.
- Structural Ponding: Older Southern Ontario buildings often lack the proper slope. Standing water accelerates membrane wear and creates “ice lensing” during our freeze-thaw winters.
How We Respond When a Tenant Calls About a Leak
We provide a 90-minute response time for service calls from our St. Catharines and Mississauga offices. Our crews arrive with fully stocked trucks to ensure the leak is contained the same day.
Once the emergency is over, we don’t just walk away. We provide a Roof Condition Report that documents the failure point, helping you decide if you’re looking at a simple one-off repair or a systemic issue that needs a capital plan.
MAXIMIZE ROOF LIFE WITH A
Preventative Roof Maintenance Plan
Avoid surprise repairs and extend the time between costly replacements with expert maintenance tailored to your roof.
Reduce costly repairs
Prevent leaks & damage
Extend roof life
Extending the Life of an Aging Multi-Res Roof
Sooner or later every roof needs to be replaced. We do our best to push that date as far out as it makes financial sense to. A few of our clients have seen their roofs run 10 or more years past the service life on the original spec, and that isn’t luck. It’s regular inspection, catching small problems before they spread, and maintaining the flashings and drains that usually fail first.
The right roof strategy depends on what the owner actually wants out of the building:
| Building Goal | The Strategy |
|---|---|
| Long-Term Hold | A Preventative Maintenance Plan with bi-annual inspections and proactive flashing repairs. |
| Pre-Sale Prep | Clearing deferred maintenance so the buyer’s inspector finds a clean bill of health. |
| Redevelopment | Strategic, targeted repairs to keep the building dry for a 2–5 year window without wasting CapEx. |
| Budget Stabilization | “Buying time” (12–24 months) so a full replacement can be properly tendered and approved by the board. |
We build the plan around the goal, not the other way around.
When Replacement Is the Right Call: A 1970s Apartment in St. Catharines
This St. Catharines apartment building had been running under the same 4-ply BUR roof since the 1970s. By the time we got up there the membrane had given out, water was getting into units below, and patch repairs were no longer holding. Drainage was the other problem: too few exit points meant water was sitting on the roof and freezing in winter, which accelerated the damage.
We stripped the old 4-ply system, installed tapered insulation starting at 5 inches in the centre and sloping down to 1 to 1.5 inches at the edges, added new external scuppers to fix the drainage, and finished with a two-ply modified bitumen system. Four days on site for a 3,000 sq ft roof.
The tapered insulation did three things at once: it tripled the thermal performance over the original fiberglass, it gave the water somewhere to go, and it eliminated the ponding that killed the first roof.
See the full St. Catharines apartment project here.
How long should a flat roof on an apartment building last?
A properly installed 4-ply BUR runs 35 to 40 years when it’s maintained. Two-ply modified bitumen runs 25 to 30 years on the same maintenance schedule. With proactive maintenance, we’ve seen both systems go 10 or more years past those numbers before replacement was needed.
Can you work on an occupied apartment building without disrupting tenants?
Yes. Most of our multi-res and condo projects are done while the building is fully occupied. We coordinate access, keep noise and debris contained, and work around tenant hours where the project allows.
What’s the difference between a BUR and a modified bitumen roof for an apartment?
BUR uses multiple plies of reinforced bitumen and is known for long service life and durability. Modified bitumen is a lighter, faster-installing system that performs well on multi-res buildings where load and installation time matter. Both are asphalt-based and handle Ontario freeze-thaw well when installed correctly.
How quickly can you respond to a leak call on a condo or apartment?
Service calls carry a 90-minute response guarantee from our St. Catharines and Mississauga offices. Our crews arrive with materials on the truck so the emergency can be contained the same day.
Get a Quote for Your Apartment or Condo
If you’re managing leak calls, planning a capital replacement, or trying to get a few more years out of an older roof before a sale or redevelopment, the first step is knowing exactly what shape the roof is in. Learn more about our flat roof replacement and repair services, then call (905) 397-1198 or contact us online for a free quote.
